I have a 95 s/t blazer that leaks trany fluid from the vent tube what would cause this.

Check your fluid level when cold and idling in park. Should be at the cold mark on the stick.
Sounds like over filled to me, but not the first time I've heard this either. For some unexplained reason, trans fluid will vent out sometimes.

Check your fluid level when cold and idling in park. Should be at the cold mark on the stick.
Sounds like over filled to me, but not the first time I've heard this either. For some unexplained reason, trans fluid will vent out sometimes.

It turns that there is a seal between the tranny and the transfer case that is no good and causing both fluids (wich are are same) to mix and cause a lot of pressure.

That's an:o easy fix! :D